Indicator



Jam. M2 i945. s. c. HAYWARD INDICATOR Filed Feb. 2, 1942 :55.2.: :If n...325.223.5215. .3

@E mmi (Ittorneg Patented Jan. 16, 1945 INDICATOR SheldonC. Hayward, Merchantville, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application February 2, 1942, Serial No. 429,228

(Cl. 40--130l 3 Claims.

My present invention relates to illuminated indicators, such, for example, -as tuning indicators for radio receivers, display signs, computing scales, etc., and has special reference to the provision of an improved indicator of the type.

incorporating a plurality of separately illuminable scales or other indicia.

The prior art recognizes two general types of selectively illuminated multi-scale indicators.

These are (a) the projection typeand (b) edge',

lighted. In the projection type indicator a translucent scale bearing surface is illuminated from the rear; the light being confined to a given scale as by means of a movable shutter or mask (see Maris 2,193,107), or by relative movement between the scale plate and light source (see Curtis, et. al. 1,877,228). Irrespective of the advantages claimed for projection type indicato-rs it may be said, generally, that they are expensive and, further, are cumbersome in that they occupy cabinet space which might otherwise be usefully employed. Edge lighted indicators, while far less cumbersome than those of the projection type, are nevertheless expensive since they have heretofore required the use oi a scale i bearing surface constituted of several glass sections (one for each scale) joined into a Continuous surface by interposed layers of an opaque material which serve to confine the light to a given scale. (As to this see White 1,741,748; Brodton 2,132,094.)

Accordingly, the principal object of my present invention is to provide an improved, selectively illuminated multi-scale indicator and one which obviates the foregoing and other less apparent objections -to analogous prior art indicators.

A related and more specific object of my invention is to provide a simple and economical means for selectively illuminatingthe individual scales of a multi-scale tuning indicator, so that the operators attention is' immediately attracted to the scale for which the range selector control is set.

Other objects and advantages will be apparent and my invention itself will be best understood by reference to the following specification and to rthe accompanying drawing, wherein Figure 1 is a front elevation; Figure 2 is a top plan view partly in section; Figures 3 and 4 are opposite elevational views of a plural scale radio tuning indicator embodying my invention.

My invention is predicated upon my discovery that if the rays of light from a lamp mounted adjacent an edge of a single sheet or plate of glass, or equivalent transparent or translucent material, are subjected to what I may designate as ,progressive reflection, the light may be conned to a given scale bearing area by means of an opaque band or ribbon applied to the outer (exposed) surface of the said plate adjacent the boundary of said scale bearing area. Hence I am able to dispense with the opaque inserts and separate scale-bearing surfaces of the prior art and mark all of the scales (or other indicia) on a single glass or equivalent translucent plate.

By progressive reflection I meant trans- Amission of the light rays 'in a Zig-zag path in `parallel to the major surfaces thereof.

While my invention is not limited by any -theory of operation I am inclined to believe that when the light is subjected to progressive reflection the majority of the rays are soon directed to the surface of the scale-bearing plate (instead of being conned to the body thereof), where they are absorbed, or otherwise prevented from spreading, by the opaque band or ribbon between the several scales.

In the drawing, wherein like reference characters are given to the same or corresponding parts in all figures, I designates generally a single, transparent, or translucent scale-bearing plate which may be constituted of ordinary glass, Lucite (i. e., methyl methacrylate resin) or equivalent material, supported in a frame comprising a pair of slotted uprights 3 and 5 into which the glass is tted. One of the minor surfaces Ia of the translucent plate I is exposed to light from a source exemplified by the separate lamps 'I and 9 and reflectors la, and 9a., respectively. A back plate II having an opaque, preferably dark, front face I Ia is supported as on the uprights 3 and 5 behind the transparent scale bearing surface I.

The top edge of the back plate II comprises a track IIb for a pointer I3 which may be moved therealong on a suitable carriage I5 as by means of a cord I 7. A front panel or escutcheon I9 (Fig. 2) frames the scale bearing portion y-of the plate I and conceals the uprights 3 and 5,

the lamps 'I and 9, the carriage I5 and the pointer driving means I'I, from view.

The transparent plate I is provided, in the instant case, with two scales A and B, respectively, Which are separated, in accordance with my invention, by means of a layer C, constituted of paint, ink, or other preferably black opaque material applied preferably in the form `of a continuous band or ribbon on the exposed major and minor surfaces of the said plate I. The opaque material may be omitted from one of the major and one or both of the minor surfaces of the plate, if desired. An ornamental design, trade-mark of the like, may be applied to the front surface of the opaque ribbon C, as indicated at C'.

As shown in Fig. l, the lamps 'I and 9 are mounted on opposite sides of the opaque ribbon C. Thus the lamp 'I supplies light for the top band scale A while the lamp 9 serves to illuminate the bottom scale B. As in standard practice the lamps 'I and .9 are adapted vto be selectively energized under the control of a suitable switcht (not shown) operated in synchronism with a conventional range `cha-nge mechanism with which the set will be understood to 'be provided. As previously indicated, in order `that the opaque ribbon or band C may vserve effectively to prevent the transmission of light from a given lamp from being transmitted to a scale other than the one to which it is allotted, it 'is `desirable tc subject Vthe light rays 'to progressive lre- `flection within the" glass so that they eventually reach the mated s rface area where they are absorbed. To ensure such progressive reflection, I prefer t( grind, etch or otherwise roughen or stipple the iinor surface or .surfaces `la of the scale bearing plate Iv though, alternatively, I can achieve substantially the same effect Without roughening the glass by so mounting the lamps V(or their filaments) that the light rays therefromimpinge the -edge of Ithe scale bearing plate vat .an angle, as indicated 4in Fig. 2, instead of being directed thereon in paths substantially parallel to the major surfaces of said plate.

l in the art.

As taught in my copending application Serial No. 332,646 (now U. S. P. 2,293,138), I may provide a reflecting surface Ib on that minor surface of the plate I which is opposite the minor 5 surface Ia upon which the light is directed. Furl5 What is claimed is:

l. In a plural scale indicator of the type incorporating a plurality of separate Sources or iight for selectively illuminating said scales, the combination with a unitary translucent plate provided with a plurality of scale-bearing areas and having a roughened 'minor surface upon which light from said source is adapted to impinge, of a light absorbent member mounted contiguous to a maj or surface of said translucent plate between said scale-bearing areas and comprising a barrier for preventing the transmission of light from the selected of said sources vthrough the selected to the nom-selected of said scales.

'2. The invention as set forth in claim 1 and 80 wherein said 4light-absorbing member comprises an adherent ribbon-like film.

t3. A device `of the character described comprising a translucent plate having `a. plurality of scale bea-ring areas thereon, a. separate source of light for each of said scale bearing areas mounted adjacent a minor surface of said Atranslucent plate for selectively illuminating said scale `bearing areas, and means comprising an adherent ribbon-like nlm constituted of a light-absorbent m material on a major surface of said plate intermediate said scale bearing areas for preventing spreading of said light from a `selected to a non- -selected of `said scale bearing areas.

5 ysHEnnoN C. 

